Treatment of hydrocarbon oils



Patented May 12, 1936 UNITED STATES PATENT OFFICE TREATMENT OFHYDROGARBON 011s Gustav- Eglofi and Jacque C. Morrell, Chicago, 111.,assignors to Universal Oil Products Company, Chicago, 111., acorporation of Delaware No Drawing. Application January 12, 1934, SerialNo. 706,409

, V V 2' Claims. (01. 196-36) This application is acontinuation in partof our application Serial No. 518,879, filed February 27, 1931.

This invention relates more particularly to the s 'refining. ofrelatively low boiling hydrocarbon distillates at elevated temperatures,especially those distillates resulting from theconversion of relativelyhigh boiling hydrocarbons at elevated I) temperatures and pressures. 10Ina more specific aspect the invention has reference to a process forrefining cracked hydrocarbon oils of approximate gasoline boiling rangeunder vapor phase conditions of treatment, using certain combinations ofgaseous treating reagents 15*and'solid contact materials which willeffect the desired. degree of refinement.

The usual method of refining cracked'distib lates is to subject them totreatment with sulphuric acid and alkaline solutions, including plumbitesolutions consisting of litharge dissolved in alkaline solutions invarious combinations of treatment, and subsequently to subject the acidtreated product to redistillation, usually in the presenceof steam.

The present invention permits the direct treatment of the hydrocarbonvapors from the cracking process, reducing the cost of reagents andeliminating the redistillation or rerunning operation, although it iswithin the scope of the invention to revaporize the product in asubsequent operation and subject thevapors to treatment as'described.

Inone embodiment the invention comprises- ,subjecting hydrocarbon oilvapors, particularly cracked hydrocarbon oil vapors of approximategasoline boiling range to treatment with sulfur trioxide and steam inthe presence of selected solid metal salts which are of a substantiallynonoxidizing character.

The salts which are preferred as contact materials to accelerate andmodify the character of the treating reactions are certainsulfates,phose phates and chlorides, principally those of the 'so-' 45, calledheavy metals. When employing sulfates an equilibrium is establishedbetween the composition of the salt and the vaporsv of sulfurtrioxide-and steam so that substantially nochemical change occurs in thecomposition of the solid 50 contact material, although there is somereductiorrof: the sulfur trioxide on account of its oxidizing actionupon the undesirable hydrocarbons and derivatives in the vaporsundergoing treatment.

55 theiicase of phosphates, many of. these are;

gradually decomposed by the action of the sulfur trioxide so that in thecourse of extended treatments the original phosphates are converted to alarge extent into corresponding sulfates of varying degrees of basicity.The rate and extent of such reactions of substitution will be determinedby the mutual influence of a large number of operating factors such astemperature, pressure, relative concentration of reacting constituents,et cetera.

In the case of chlorides, the reaction of the sulfur trioxide thereon isusually more rapid so that the reactions of treatment are alteredconsiderably due to the presence of the vapors of hydrochloric acid.

The following sulfates are" adaptable to use in treatments conductedaccording to the invention:

Aluminum sulfate Zinc sulfate, Y Stannic sulfate Cupric sulfate Plumbicsulfate Mercury sulfate (basic) Nickel sulfate Manganic and manganoussulfates Cadmium sulfate Under the preferred conditions of'temperaturewhich will bejgiven hereinafter, it hasbeen found to be preferable to.use. only sulfates which are solid; under the conditions of treatment.This usually eliminates the'use of sulfates of cobalt and of' chromiumon account of their tendency to flux. -A sulfate of vanadium knownas-vanadyl sulfate finds application in some instances.

The following phosphates may be employed: Aluminum phosphate Zincphosphate Lead phosphates (includes a pyrophosphate) Ferric phosphate 0Nickel phosphate. Chromium phosphate Manganese phosphates Vanadiumpyrophosphate Cadmium phosphate 7 In. the phosphate group may also bementioned phospho-molybdates and phospho-tungstates.

. The number of chlorides which may be successfully employed as contactmaterials is somewhat limited by practical considerations as to cost,

melting point. and volatility. Many compounds which would be utilizableinliquid phase treatmentsfare ruled out by meltingpoint and boilingpoint considerations. The following chloridesr5 may be used underproperly regulated operating 7 conditions:

Zinc chloride Cadmium chloride Cupric chloride Manganese chloride 7 VMolybdenum chlorides (di, tri and tetra) Chromic chloride 'It is withinthe scope of the invention to employ as solid contact materials singlechemical corn-- 7 pounds selected from the above mentioned groups ormixtures of the same which'may be foundto give good treating effectsupon any given distillate which may be treated' It is to be understoodthat each. specific contact substance or mixture of different chemicalcompounds :will exert its own peculiar catalytic or chemical influenceupon the course and extent of the treating reactions so that'thedifferent contact materials are not to be considered'as exactequivalents though they may assistin producing somewhat-analogoustreating effects.

.Of the compounds mentioned asbeing utilizable some may beartificially'prepared and some may be used as minerals as they aremined.

In applying the process of the invention to practice any suitableequipment may be employed which will permit the contacting of thehydrocarbon vapors and the sulphur trioxide and steam i ;with the flowwith the metal salts; for example, a suitable tower treating vesselcontaining the contact salts. In

lieu of direct packing of the tower or treating vessel with the metalsalts an inert filling material such as Raschig rings, firebrick,crushed rock, gravel, crushed ceramic material, and the like, suitablymixed or coated with a salt, maybe employed. Similarly, any device whichpermits the efilcient contacting of the vapors undergoing treatment'withsalts may be employed.

The tower or treating vessel containing the contact material may bedirectly connected to a cracking unit or to a rerun or redistillationunit so that the vapors arising therefrom may be' treated in the mannerdescribed.

It has been found desirable to neutralize the distillate immediatelyafter condensation either by passing the condensate directly through abody of alkal such as a solution of caustic soda or by washing thedistillate free of sulphur oxides with water and/or alkalis, such as asolution of caustic soda, ammonia, or the like. The neutralizing agentmay also be introduced into the vapor line leading to the condenserorinto the condenser itself.

The amount of sulphur trioxide employed may vary from a fraction of apound to, several pounds, based on a barrel of hydrocarbon distillatetreated.

Various temperatures of treatment may be employed, for example, from250600 F., more or 7 less, and the pressures may be sub-atmospheric,atmospheric, or superatmospheric.- While the results may vary with thetemperatures employed,

the pressures and temperatures are chosen so that the hydrocarbons aretreated substantially in'the vapor phase.

In order to reduce the intensity of the reaction the sulphur trioxidemay be admixed with an inert gas and a flue gas carbon dioxide and thelike and may be introduced at various successive points in the treatingtower.

The effects produced upon oil vapors, particu larly those produced fromthe cracking of heavy hydrocarbon oils by the use of gases and solidcontact substances characteristic of the'invention are in general thoseof polymerization or condensation of relatively highly unsaturatedhydrocarbons or their derivatives, particularly their sulfurderivatives. The net result is the controllable elimination of groups ofcompounds which are readily polymerized under oxidizing conditions toformsubstances of a gummy or resinous nature which are undesirable inmotor fuel.

The treatment herein described may constitute the sole refining actionon the oil, or it may constitute one'step in a series of refining steps.It maybe preceded by the usual treatments with refining agents such assulphuric acid, caustic soda, plumbite, filtering earth or the like, andmay be succeeded by any combination of the above refining agents,followed, if desired, by distillation.

As specific examples of the operation of the process of the inventionand of the results ob tained by its use, the following may be given:

(1) A California cracked distillate of approximately motor fuel boilingrange may be vaporized and subjected to treatment with a mixture ofsulfur trioxide and steam during the passage of the vapors in thedownward direction through a stationary contact mass consisting of amixture of a finely divided zinc sulfate. supported.

on fullers earth, the weight of the earth being sulfur trioxide may beusedin an amount equivalent toapproximately three pounds per barrel ofoil. The untreated product may show a gum content of approximately 500mgs. per 100cc. and have a reddish brown color, with a sulfur content ofapproximately 0.45%. product after suitable separation from spentreagents, neutralizing with alkalis and washing with water, may show agum content of approximately 30 mgs. and a color of+25 on the Sayboltscale. The sulfur content may be found to be as low as 0.2%.

.(2) In the case of a mixed Mid-Continent The treated and West Texascracked distillate treated with cases the untreated distillates maycontain 650 mgs. of gum and have a dark reddish color while the treateddistillatesmay have a gum content of only 40 mgs. and a color of 25 to,30 on the Saybolt scale. The sulfur content may be reduced from 0.5% to0.15%.

'The foregoing description andexamples have disclosed a processapplicable to the treatment of hydrocarbon oil vapors which has a wideapplicability and is capable of great variation in the methods ofoperation and the amounts of reagents employed. Therefore, the specificcases cited are not to be construed in a limiting sense upon the broadscope of the invention as many other modifications can be used andexamples of results therefrom given.

We claim as our invention:

1. A process for refining hydrocarbon oil which comprises subjectingsaid hydrocarbon oil in vapor form to the action of sulphur trioxide andsteam in the presence of zinc sulfate.

2. A process for refining hydrocarbon oil which comprises subjectingsaid hydrocarbon oil in vapor form to the action of sulphur trioxide andsteam in the presence of finely divided zinc sulfate and fullers earth.

GUSTAV EGLOFF'. JACQUE C. MORRELL.

